Investigation of the Slow- and Fast-Light Effect on the Basis of Stimulated Brillouin Scattering for Application in Optical Communication and Information Systems

TitleInvestigation of the Slow- and Fast-Light Effect on the Basis of Stimulated Brillouin Scattering for Application in Optical Communication and Information Systems
Publication TypeThesis
Year of Publication2010
AuthorsHenker, R
Academic DepartmentSchool of Electronic and Communications Engineering
Date Published2010
UniversityDublin Institute of Technology
CityDublin, Ireland
Thesis TypePhD Thesis

In today's information age demand for ultra-fast information transfer with ultra-high bandwidths has reached extraordinary levels. Hence, the transmission in the future internet-backbone will be increasingly constrained in the network nodes. At the same time, the power consumption of the network systems will increase to unsustainable levels. To overcome these constraints power-efficient photonic networks which provide ultra-fast all-optical switching and routing are essential. Nowadays, optical signal processing and switching can be implemented relatively easily. However, the realization of optical buffers and short-term memories is still an unsolved challenge.

The slow- and fast-light effect has been investigated as one solution for the optical buffering over the last few years. It means the slowing down and acceleration of the group velocity of light pulses in a medium. To realize this, many different methods and material systems have been developed but due to its significant advantages the nonlinear effect of stimulated Brillouin scattering (SBS) is particularly promising. However, it also suers from disadvantages which limit the slow- and fast-light performance.

In this thesis the slow- and fast-light effect using SBS is investigated. SBS-based slow- and fast-light utilizes the generation of artificial resonances by the coupling of a strong pump wave inside an optical fiber. This creates gain and loss regions in which a counterpropagating signal wave can be amplified and attenuated, but slowed down and accelerated as well. The properties of such a system depend directly on the Brillouin spectrum. Thus, the focus of this work is the analysis of opportunities to overcome the natural limits of SBS-based slow-light by the optimization of the transfer function. Therefore, different novel methods for a bandwidth enhancement, an enhancement of the maximum achievable time delay and a reduction of the output pulse distortions are investigated in theory and experiment. This includes the theoretical background and practical limits of these methods. The most important results are a bandwidth enhancement to a multiple of the natural Brillouin bandwidth up to the GHz range, a time delay enhancement of up to four times of the initial pulse width and a significant distortion reduction of the output pulses by 25 %.

Although there are various potential applications for the slow- and fast-light effect, this work examines the topic mainly under the aspect of information and communication systems. Thus, this thesis will show that SBS-based slow- and fast-light is a reliable and efficient candidate to realize all-optical short-term buffers. Despite the small storage capacity compared to other techniques, it can be used for an accurate synchronization, multiplexing and equalization of multiple high bit rate data channels as well as or phased array antennas.


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